Collision Glial Neoplasms Arising in an Ovarian Mature Cystic Teratoma: A Rare Event

Figure 1

Hematoxylin and eosin (H&E) stains and immunohistochemistry. (a) Low-power field examination shows cystic spaces lined by mature squamous cell epithelium with underling pilosebaceous units and adjacent pilocytic astrocytoma (H&E, 4x). (b) Bipolar cellular neoplasm of low-grade cytology along with tapered corkscrew-shaped brightly eosinophilic hyaline material (Rosenthal fibers) (H&E, 40x). (c) A low-power field demonstrates a separate focus of subependymoma comprised of bland monomorphic cellular proliferation in a dense, fine, glial fibrillary background (H&E, 2x). (d) Clusters of isomorphic nuclei with occasional pseudorosettes (H&E, 40x). (e, f) GFAP revealed strong diffuse staining in the pilocytic astrocytoma and in the subependymoma (f), respectively (40x). (g): S100 revealed strong diffuse staining in the subependymoma (40x).

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